Anaesthetics are frequently used to prevent injuries, stress and to promote welfare while handling animals.
The efficiency of five anaesthetics for short-term handling of the European cuttlefish (Sepia officinalis) was
tested in order to determine the best agent and its concentration. Ethanol (10.0, 20.0 and 30.0 mL.L−1),
clove oil (0.05, 0.15 mL.L−1), hypothermia (8 °C), magnesium chloride (hexahydrated; 20.0, 27.0 g.L−1)
and AQUI-S® (10.9 μl.L−1) were the selected anaesthetics. This choice was preceded by a preliminary trial,
with additional agents, where 2-phenoxyethanol (10, 15, 20, 30 mL.L−1) and MS-222® (30, 40 mg.L−1)
were used. Due to the lack of reliable results from these two agents, they were discarded. Anaesthetic procedure was performed in 85 cuttlefish juveniles with a mean wet weight of 45.69±12.01 g, on a 5 L container, under hyper-oxygenated seawater (~200%), plus the dose of a given anaesthetic agent. After achieving induction, cuttlefish were handled for 180 s, which consisted in a weighing procedure according to a developed CCMAR protocol. Recovery from anaesthesia was performed in a tank with flow-through hyper-oxygenated water. All these procedures were video recorded and used to, a posteriori, obtain the time frames of induction, handling and recovery, as well as for the behaviour analysis during each stage.